Holding means for instruments



June 9, 1931. N. c. SHAW ETAL 1,809,639

HOLDING MEANS FOR INSTRUMENTS Filed Jan. 22, '1931 Fig.1.

IN VEN TORS /V. 6.3 am a y T, M arm,

(TL/W ATTORNEY.

underside of the top plate, in pole pieces 2,

Patented June 9, 1931 UNITED s'ra'rlezs PATENT OFFICE NOBLE C. SHAW, OF SWISSVALE, AND THOMAS J. OM EAR-A, OF PITTSBURGH, PENN- SYLVANIA, ASSIGNOBS TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA HOLDING MEANS FOR INSTRUMENTS Application filed January 22, 1981. Serial No. 510,578.

Our invention relates to holding means for instruments, and particularly to holding WVe will describe one form of relay having ap lied thereto one form of holding means em fwodying our invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view partly in side elevation and partly in cross section, showing one form of relay having applied thereto one form of holding means embodying our invention. Fig. 2 is a fragmentary bottom view of a portion of the relay shown in Fig. 1.

Similar reference characters refer to simi-' lar parts in both views. I

Referring first to Fig. 1, the reference character A designates the top plate of a relay, which top plate supports all of the operating mechanism of the relay. Mounted on topplate A-is the usual electromagnet B,

the cores 1 of which extend downwardly through the top plate and terminate, on the only one core and one pole piece being visible in the drawings. Attached to the pole pieces 2 by means of screws 3 is a bracket 4', and pivotally supported on pivot pins 5 carried by bracket 4 is an armature 6 which isadapted to be attracted toward the pole pieces 2 when magnet B is energized, and to fall away therefrom by gravity when the magnet is deenergized The armature is prevented from actually touching the pole pieces 2 by means of the usual core pins 7 attached to thepole pieces, while the movement of the armature away from the pole pieces is limited byv a back stop 8 which is secured to the top plate A. Fixed to the underside of the arma ture is aninsulating support 18 carrying two superposed contact fingers 9 and 10. The contact finger 9 isadapted to make contact with a fixed front contact 12 when the armature is attracted toward the pole pieces 2, and the contact finger 10 is adapted to make con tact with a fixed back contact 11 when the armature falls away from the pole pieces. The fixed contacts 11 and 12 are attached to the top plate A by means of terminal posts 13 and 14, respectively. Electrical connection to the'contact fingers 9 and 10 is madev bv means of a flexible connector 15 which is,

attached at one end to both contact fingers, and at the other end to a bracket 15 which is secured to the top plate A by means of a terminal post 16.

The armature and contacts are enclosed in a suitable casing C which, in the form here shown, is glass, thiscasing being held inplace against the underside of the top plate A by means of a suitable fastening device 17 which surrounds the casing, and which is secured to the top plate in any suitable manner forming no part of our present invention and therefore not shown in the drawings.

7 The contact fingers 9 and 10 are accurately adjusted when the relay is assembled, and unless suitable means are provided for restraining the movement of the armature, this adjustment is liable to be destroyed by jars or shocks during shipment ofthe completedre lay. The means here shown for restoring the movement of the armature comprise a screw 19 provided at its lower end with a saw kerf or slot 20 adapted to accommodate a screw driver or other suitable tool. A coil spring 28 surrounds a portion of the screw 19 adjacent the slot 20 and has its upper end secured in the top ofthe slot in any suitable manner. The screw 19 is adapted to be screwed through a tapped hole 21 in the armature as will be explained hereinafter, and the free end of the spring 28 is adapted to cooperate with -a screw plug 22 which is screwed into a bushing 23 inserted in the bottom of the glass casing C. I

The bushing 23 is constructed of some suitable material, such as brass, and is prevented from turning by a square portion 23 which fits into a square recess 24 formed in the underside of the casing C. A cushion washer 25 of suitable material such cork or felt, is inserted between the square portion of the bushing and the top of the recess 24a, and this washer is made sufficiently large so that it turns down around the square portion of the bushing (see Fig. 2) thus preventing injury to the casing due to any tendency of the bush ing to turn when the plug 22 is tightened in the bushing. The cylindrical portion 23" of the bushing extends upwardly through a suitable hole 24 in the casing, and the upper end thereof is spun over against a metal washer 26, a cushion washer 27 being inter posed between the metal washer and the casing to equalize the pressure and. prevent dami age to the casing during the spinning operation. The cushion washers 25 and 27 also serve to prevent the entrance of moisture or dirt into the casing at the bushing 23.

The operation of the holding means embodying our invention is as follows: After the relay has been assembled and adjusted the screw 19 and the spring 28 are passed up wardly through the hole 23" in the bushing 23, and the screw is then screwed through the tapped hole 21 in the arn'iatureG far enough so that, when the armature occupies a position approximately midway between its extreme positions, the upper end of the screw will engage the underside ofihe top plate A. The turning of the screw may be accomplished either by grasping the lower end or the spring 28 with the fingers, or by inserting a screw driver or other suitable tool through the spring into engagement with the slot, 20 in the lower end of the screw 19. After the screw has been screwed through the armature to the desired position, the spring 28 is compressed by screwing plug 22 into the threaded hole 23 in the bushing 23, and the armature is then held in an intermediate position by a force which depends upon the stiffness and amount of compression of the spring. It will be apparent that this force may be adjusted to any desired value by employing a spring having the proper length and necessary stiffness.

One advantage of holding means embodying our invention is that diificulties in assembling the holding device due to misalignment of the hole in the armature and the hole in the bushing are completely eliminated. This is important because considerable difficulty is encountered in holding molded prod ucts such as the glass CtlSll'lg C to exact dimensions, and also in holding the casing in a detinite position with respect to the top plate.

Another advantage of holdng means our bodying our invention is that during assembly of the holding means, it is impossible to exert excessve strain on the pivot pins 5 which support the ari'nature.

Still another advantage of holding means embodying our invention is that possible damage to the pivot pins which support the armature and misalignment of contacts caused by movement of the casing with respect to the top plate and the remainder of the relay assembly as a result of rough handling during shipment are positively prevented, because the only ei'lect of such move ment is to bend the spring a slight amount which will not exert any strain on the armature supports or alter the vertical position of the armature.

Another advantage ot holding means embmlying our invention is that when the relay is ius-itailed in service, if the screw 19 is not ren'loved, all circuits controlled by the relay ill remain open and no damage can result. This feature is of particular importance in the case of relays employed in railway signaling, because if the screw is no removed, a false clear signal cannot resuit, as has sometimes been the case when holding means have been employei'l which hold the arn'iature rigid with one of contacts closed during shipment.

Although we have herein shown and described only one form of holding means embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without de 'zarting from the spirit and scope of our invention.

Havin thus described our invention, what we claim is:

1. In combination, an instrun'ient having a fixed part and a movable member, a second member attach ad to said movable member in such manner that said second member will engage said fixed part when said movable member occupies an intermediate position, and resilient means cooperating with said second member for holding said second memher in the position in which said second member engages said fixed part.

2. In combination, an instrument comprising a fixe l part and a movable member car ried thereby, a screw threaded through said movable member and adapted to engage sai d iii-(ed part when said movable member occupies a predetermined position, and resilient means cooperating with said screw for holding said screw in engagement with said lined part.

3. In combination, an inr itrument comprising a fixed part and a movable member carried thereby, said member being provided with contacts one of which is closed when the member occupies one position and another of which is closed when the member occupies another position, a screw threaded through said movable member in such manner that said screw will engage said fixed part when said member occupies an intermediate position in which both Contacts are open, and resilient means associated with said screw for biasing said screw into engagement with said fixed part.

4:. In combination, an instrument comprising a fixed part and a movable member, an enclosing casing for said movable member, a screw threaded through said movable member in such manner that said screw will en gage said fixed part when said movable member occupies an intermediate position, a spring cooperating with said screw, and means associated with said casing for compressing said spring to bias said screw to the position in which it engages said fixed part.

5. In combination, an instrument comprising a fixed part and a movable member carried thereby, an enclosing casing for said member, a screw adapted to be threaded through said movable member in such manner that one end of said screw will engage said fixed part when said member occupies an intermediate position, a compression spring fixed to the other end of said screw, said casing being provided with a bushing having a threaded hole which is large enough to permit said screw to be screwed through or removed from said member without removing the casing, and a plug screwed into said hole for compressing said spring, whereby said screw is held in engagement with said fixed part.

6. In combination, an instrument casing provided with a hole and with a recess at one end of said hole, a bushing extending through said hole and provided with a. portion which engages said casing at said recess to prevent said bushing from turning,

a first cushion washer interposed between said portion and said casing, a second cushion washer surrounding said bushing 0n the other side of said casing from said recess, and a metal washer adjacent said second cushion washer, the end of said bushing being spun over against said metal .wa-sher'to fasten said bushing to said casing.

7. In combination, an instrument casing provided with a hole and having a square recess at one end of said hole, a bushing extending through said hole and provided with a. square portion which fits into said square recess to prevent said bushing from turning, a metal washer surrounding said bushing on the opposite side of said casing from said square portion, the end of said bushing being spun over into engagement with said metal washer to fasten said bushing to said casing, and two cushion washers, one interposed between said metal washer and said casing and the other interposed between said square portion and said casing, said cushion washers serving to prevent damage to said casing while the end of said bushing is being spun over.

8. In combination, an instrument casing comprising a fixed part and a movable member, an enclosing casing for said movable member, said casing being provided with a hole and with a rectangular recess at one end of said hole, a bushing extending through said hole and having a rectangular portion fitting in said rectangular recess to prevent said bushing from turning, said bushing also being provided with a threaded hole, a metal washer surrounding said bushing at the opposite side of said casing from said rectangular portion, the end of said bushing being spun over into engagement with said washer for holding said bushing in place, two cushion washers one interposed between said metal washer and said casing and the other interposed bet-ween said rectangular portion and said casing, a screw adapted to be screwed into said armature in such manner that one end of said screw will engage said fixed part when said movable member occupies an intermediate position, a compression spring attached to the opposite end of said screw, said spring and said screw having diameters which are smaller than the diameter of the hole in said bushing, and a plug adapted to be screwed into the hole in said bushing for compressing said'spring to hold said screw in the position in which said screw engages said fixed part.

In testimony whereof we aflix our signatures.

' NOBLE C. SHAW.

THOMAS J. OMEARA. 

